Listen to Robert Emmerich introduce The Big Apple, a hit song from 1937. Music written by Bob and performed by Tommy Dorsey's Clambake Seven with Bob on piano. Lyrics written by Buddy Bernier and sung by Edythe Wright. Audio provided by Dorothy Emmerich.

"Don’t send a boy to do a man’s job/work” means that one should not have someone do what that person cannot do. “Hire a boy to do a man’s business; he will make up his wages in the spoiling of your tools” was cited in 1860.

“Never send a boy to do a man’s work” was cited in print in 1874 and “Don’t send a boy to do a man’s job” was cited in print in 1920. “We won’t send a girl to do a woman’s job” was cited in an advertisement for temporary services in 1966.

TV TropesNever Send an X to Do a Y’s Job
A stock phrase, said when one character has to take care of something another tried and failed to do. The most common phrasing is, “Never send a boy to do a man’s job.”

Google BooksOptimism:
The Lesson of Ages
By Benjamin Paul Blood
Boston, MA: Bela Marsh
1860
Pg. 92:
Hire a boy to do a man’s business; he will make up his wages in the spoiling of your tools. Though he may do well for a while, some accident will revenge your penuriousness.

12 October 1874, The Daily Graphic (New York, NY), pg. 736, col. 4:
Never send a boy to do a man’s work.

Google BooksThe History of the United States:
Told in One Syllable Words
By Josephine Pollard
New York, NY: McLoughlin Brothers, Publishers
1884
Pg. 31:
It is not well to set a boy to do a man’s work.

Google Books
December 1890, The Indicator, pg. 583, col. 1:
I quoted the old saying: “Never send a boy to do a man’s work,” and commented on it in a facetious manner; ...

Google Books
9 April 1956, Life magazine, “Man in a Gray Flannel Trap,” pg. 111, col. 2:
The movie’s producers acted on an old maxim Madison Avenue is fond of mouthing, “Don’t send a boy to do a man’s job,” and threw $4 million (including a $1.5 million cast) into Man.

Google BooksDun’s Review and Modern Industry
Volume 88
1966
Pg. 66 ad:
We separate the women from the girls. And that’s what separates us from other temporary services. We won’t send a girl to do a woman’s job.

Google BooksThe Dictionary of Modern Proverbs
Compiled by Charles C. Doyle, Wolfgang Mieder, and Fred Shapiro
New Haven, CT: Yale University Press
2012
Pg. 25:
A boy cannot do a man’s work.
1904 Charles Richmond Henderson, Introduction to the Study of Dependent, Defective, and Delinquent Classes, 2nd ed. (Boston: D. C. Heath) 180: “Mr. A. Johnson makes a distinction, however, which should be noted. A boy cannot do a man’s work; if he could he would be more than self-supporting, for a man must support several persons by his labor.” DAP 64. In contrast to the (slightly) older “Don’t send a boy to do a man’s job,” the proverb “A boy cannot do a man’s work”—in one of its applications, at least—has more to do with economics than with competence.